From 6a93b22bc8569315b2e0ce07297b73673882925a Mon Sep 17 00:00:00 2001 From: David Gibson Date: Sun, 28 Oct 2007 22:20:34 +0100 Subject: hugetlb: check for brk() entering a hugepage region Unlike mmap(), the codepath for brk() creates a vma without first checking that it doesn't touch a region exclusively reserved for hugepages. On powerpc, this can allow it to create a normal page vma in a hugepage region, causing oopses and other badness. Add a test to prevent this. With this patch, brk() will simply fail if it attempts to move the break into a hugepage reserved region. Signed-off-by: David Gibson Signed-off-by: Adrian Bunk --- mm/mmap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index f2ac461a357e..a04576de3254 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1870,6 +1870,10 @@ unsigned long do_brk(unsigned long addr, unsigned long len) if ((addr + len) > TASK_SIZE || (addr + len) < addr) return -EINVAL; + error = is_hugepage_only_range(current->mm, addr, len); + if (error) + return error; + flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; error = arch_mmap_check(addr, len, flags); -- cgit v1.2.3